Cam lapping machine



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Filed Jan. 27, 1945 :s Sheets-Sheet 2- gr vucmm V HERBERT 5. lNDtiE Aug. 27, 1946. 5, |NDGE v 7 2,406,689

CAM 'LAPPING MACHINE Filed Jan. 27, 1945 3 Sheets-Sheet 3 /a m O ,5 b 4 $3 HERBERT 5. inm a warren lapping. machine; Fig. 2 is a fragmentary diagrammatic perspective View of theeam. lapping machine;

Patented Aug. 27,1946

stares earner or ies CAM LAPPING MACHINE Herbert S. Indge, Westboro, Mass, assignor to Norton Company, Worcesten-Mass, a corporation of Massachusetts Application January 27,1945, Serial No. 574,847

This invention relates to grinding machines, and more particularly to a cam lapping machine.

One object of the invention is to provide a simple. and thoroughly practical lapping machine for lapping a cam to a predetermined finish and contour. Another object of the invention is to provide a cam lapping machinewith an. automatically actuated abrasive paper feed which continuously presents a fresh abrading surface during the lapping operation, A further object of the invention is'to provide. a cam lapping machine inwhichthe. lapping 'arm is'controlled by 7 Claims. (Cl. 51 154)- a master cam positicmed in axial alignment with and rotatable with the cam to be lapped so as to eliminate the necessity or providing synchronous driving mechanis-mbetween the master cam and'the cam to be lappedi.

Another object of the invention is to provide a cam lapping machine having a, pivotally mounted cam'lapping arm the movement of. which is'controlled by a master cam mounted on the arbor supporting the cam to be lapped. A further object of the invention is to provide a cam lapping ma chine with a. pivotally mounted cam lapping arm, the movement of which is controlled by a pivotally mounted arm carryinga follower which engages amaster cam mounted on the same arbor with the camto be lapped; A further object of the in vention is to providea manually operabletoggle operated mechanism to move the cam lapping arm and the follower supporting arm toand fromv an operative position. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in'the following claims.

In the accompanying drawings in which is shown one of various possible embodiments ofthe mechanical features of this invention,

Fig." l. is a. frontelevation of the improved cam Fig. 3 isairagmentary side elevation, on an enlarged scale, showing the cam lapping arm and the abrasive paper feed mechanism; and

Fig. 4 is a fragmentary side elevation. on, an enlarged scale, of the operating end of the cam lapping arm.

A lapping machine has-been illustrated in the I 2 supporting table ll. In order to facilitate a free and easy reciprocatory movement of the table, it

is preferably supported on an anti-friction slideway comprising a pair of rows of spaced antifriction balls Hand. I3 (Fi 3).

The table II is preferably arranged so that it may be reciprocated during the lapping operation to produce a break-up motion between the work to be lapped and the lapping element. An electric motor M is mounted on a bracket l5 which is fixed to the base of the machine. The motor [4 is provided with a driving pulley l6 which is connected by a V-belt I with a pulley l8 mounted on the drive shaft of a speed reduction unit IS. The speed reduction unit 19 is provided at its upk per end with a positively driven eccentrically positioned stud (not shown) Which is operatively connected to the left-hand end of a connecting rod 28.. The other end of the connecting rod 25! a footstock 23 which are providedwith Work supporting centers 24 and 25', respectively. .A driving mechanism is rovided for rotating the work arbor 2! during a lapping operation comprising an electric motor 26 which is supported on a bracket 21 fixed relative. to the base IQ of the machine;

The motor 215 is provided with an armature shaft 28 which serves as a support for a multi-V-groove pulley-29. The pulley 29 is connected by a V-belt 3!! witha V-groove pulley 3! mounted on the lefthand end of the headstock spindle (not shown).

Thework supporting arbor 2! serves as a sup- 1 port for a master cam 35 and a cam to be lapped drawings comprising a base Ill whichjserves as a support-for a longitudinally reciprocable work 36. The arbor 2! is preferably-formed so that thecam to be lapped may be positioned, thereon fora lapping operation to locate it in predetermined timed relation to the master cam 35. In order to lap the cam 36 to the desired and predetermined finish and contour, a pivotally mounted lapping element is provided comprising a lapping arm 38 which is pivotally mounted on a shaft 39 which. is supported by a bracket 46 which is fixed relative-to the base to of the machine. The lapping arm 38 is normally urged into operative engagement with the cam 36 to be lapped by means of atension spring M the upper end of which is connected to a stud42 on the arm 38 (Fig. 3) and the lower end of which is fastened to the bracket 40. In order yieldably to support a lapping element, a resilient supporting shoe is preferably provided which in the present instance comprises an endless leather belt 43 which is passed around a pair of collars 44 and 45. The collars 44 and 45 are supported by studs 46 and 41, respectively, which are carried by the lapping arm 38. The stud 46 is provided With an eccentric portion for supporting the roller 44 so that the roller 44 may be adjusted relative to the roller 45 to facilitate tensioning the belt 43 as desired.

It is desirable to provide a flexible abrading or lapping element, preferably comprising a continuous strip of abrasive paper which may be continuously fed during the lapping operation so as at all times to present a fresh abrading surface to lap the face of the cam. A reel of abrasive paper 48 is mounted on the upper end of an arm 49. The abrasive paper 50 passes from the reel 48 around the nose of the lapping arm formed by the belt 43 and passes backwardly between a pair of pinch rolls or gears and 52, respectively. The gears or pinch rolls 5| and 52 ar rotatably supported by studs 53 and 54, respectively, the ends of which are supported in brackets 48 and 40a which project upwardly from the base it] of the machine. I A motor driven mechanism is provided for continuously rotating the pinch rolls 5! and 52 at a slow uniform rate during the entire lapping operation. This mechanism comprises an electric motor 55 having an integrally mounted gear reduction unit 55 formed integrally therewith. This motor 55 and speed reduction unit 56 may b any of the standard and well known units in common use today such as, for example, the Bodine reducer motor. This reducer motor unit 50-5l is fixedly supported on the bracket 50a and serves positively to drive the pinch roll or gear 5| so as continuously to draw the abrasive paper from the reel 48 over the nose of the lapping arm 38 and pass the worn abrasive paper 50 toward the rear of the machine. readily apparent from the foregoing disclosure that a fresh abrading surface is continuously being provided during the entire lapping operation.

In order to control the swinging movement of the pivotally mounted lapping arm 38, a pivotally mounted follower arm 60 is pivotally mounted on the shaft 39 and spaced from the lapping arm 38. The forward end of the follower arm 6!! is provided with a follower roller 6| which is arranged to engage the master cam 35 during a lapping operation. The follower roller 6%) is preferably of a diameter equal to the abrasive covered nose of the lapping arm 38.

In order that the master cam 35 and follower arm 60 may control the swinging movement of the lapping arm 38, the lapping arm 38 is provided with a stud 62 which is fixed relative to the lapping arm 38. The stud 62 passes through an elongated aperture 63 (Fig. 3) formed in the follower arm 65. the follower arm an to locate the stud 62 relative to the follower arm 60. In order to provide a yieldable connection therebetween, a compression spring 65 is contained within an aperture 66 formed in the follower arm 68. The lower end of the compression spring 55 engages the stud 62 and the upper end thereof is engaged by a screw 61 by means of which the tension of the spring 65 may be varied as desired. It will be readily apparent from the foregoing disclosure that by adjusting the screw 64, the position of the fol- It Will be A stop screw 64 is provided on r" lower roller 6! relative to the nose of the lapping arm 35 may be readily adjusted as desired and that the provision of the spring provides a yieldable connection between the lapping arm and the follower roll supporting arm 60.

It is desirable to provide a suitable mechanism for swinging the lapping arm together with the follower arm 55 to and from an operative position. This mechanism may comprise a manually operable lever 1!] which is pivotally mounted on the stud H. A toggl lever 12 is also mounted on the stud H and is fixedly supported thereon so that the lever 10 and the toggle lever 1.2 form a bell crank lever. The lower end of the toggle lever 12 is connected by a stud 13 with a toggle lever 74 which is pivotally mounted on a stud 15 which is fixedly supported on the bracket 40. A pivotal support is provided for the stud H comprising a pivotally mounted link 16, the left-hand end of which is mounted on a stud 11 carried by the bracket 45.

In the full line position of the parts as shown in Fig. 3, that is, with the lever 15 in a downward or horizontal position, the lapping arm 38 and the follower arm 65 are in operative positions with the abrasive paper 50 engaging the cam 36 to be lapped and the follower roller 6| engaging the master cam 35. has been completed, the lever 10 may be moved in a counterclockwise direction into the dotted line position Illa (Fig. 3) so that the toggle levers l2 and i4 assume positions 12a and 74a (Fig. 3), thus serving to raise the follower arm 58 and the lapping arm 35 out of engagement with the master cam 35 and the cam 35. l

The operation of this improved cam lapping machine will be readily-apparent from the foregoing disclosure. A cam 36 to be lapped is mounted in position on the arbor 2|. The arbor 2i supporting the master cam 35 and the cam to be lapped 36 is then mounted in position, being rotatably supported by the headstock center 24 and the footstock center 25. After thework has been thus positioned, the motor !4 is set in motion to cause a reciprocatory motion of the table I I, the electric motor 26 is set in motion to rotate the work arbor 2|, and the motor 59 is started to provide a continuous feeding movement of the strip of abrasive lapping paper 5!]. The control lever Ill may then be swung from the dotted line position 700, into the full line position 70 (Fig. 3) so as to shift the toggle levers l2 and 14, thus allowing the lapping arm 38 and the follower arm 60 to swing downwardly under the tension of the spring 4| until the master cam roller Bl engages the master cam 35 and the abrasive paper 5!! engages the cam 36 to be lapped. The lapping operation may be continued for the desired time interval, that is, until the surface of the cam being lapped has been lapped to the desired finish and contour during which time the abrasive paper 50 is advanced continuously during the entire lapping operation. After the lapping operation has been completed, the lever '10 may again be swung into dotted line position 70a to raise the lapping arm 38 and the follower arm 60 to inoperative positions so that the abrasive paper 50 and the follower roller 6| are out of engagement with the cam 35 and the master cam 35, respectively.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodi- After the lapping operation ments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a cam lapping machine having a base, a rotatable work support including a headstock and a footstock, a work supporting arbor for supporting a cam to be lapped, a movably mounted cam lapping arm on said base having a nose piece, a flexible abrasive lapping element on said arm surrounding said nose piece, a master cam on said arbor adjacent to the cam to be lapped, a movably mounted arm having a rotatable follower roller in engagement with said master cam, yieldable means to maintain said follower roller in engagement with said master cam, interconnections between said cam lapping arm and said follower whereby said follower roller imparts a controlled movement to said lapping arm and element, and manually operable means simultaneously to move said lapping arm and said follower arm to and from an operative position.

2. In a cam lapping machine having a base, a rotatable work support including a headstock and a footstock, a work supporting arbor for support ing a cam'to be lapped, a, pivotally mounted cam lapping arm on said base having a semi-cylindrical nose piece, a flexible abrasive lapping element on said arm surrounding said nose piece, a master cam on said arbor adjacent to the cam to be lapped, a pivotally mounted arm having a rotatable follower roller in engagement with said master cam, yieldable means to maintain said follower roller in engagement with said master cam, interconnections between said cam lapping arm and said follower whereby said follower roller imparts a controlled swinging movement to said lapping arm and element, and means including a manually operable lever simultaneously to Swing said lapping arm and said follower arm to and from an operative position.

3. In a cam lapping machine having a base, a rotatable work support including a headstock and a footstock, a work arbor supported thereby to support a cam to be lapped, a pivotally mounted cam lapping arm on said base having a nose piece, a flexible abrasive lapping element on said arm which wraps around said nose piece, a master cam on said arbor adjacent to the cam to be lapped, a pivotally mounted arm having a rotatable follower roller in engagement with said master cam, yieldable means to maintain said follower roller in operative engagement with said master cam, adjustable connections between said follower arm and said cam lapping arm whereby said lapping element may be adjusted relative to said master cam follower roller, and manually operable means simultaneously to swing said lapping arm and said follower arm'to and from an operative position.

4. In a cam lapping machine having a base, a rotatable work support including a headstock and a rootstock, a work arbor supported thereby for supporting a cam to be lapped, a pivotally mounted cam lapping arm on said base, a lapping element on said arm, a master cam on said arbor adjacent to the cam to be lapped, a pivotally mounted arm having a rotatable follower roller in engagement with said master cam, yieldable,

means to maintain said master cam roller in operative engagement with said master cam, ad-' justable connections between said follower arm and said cam lapping arm whereby the lapping element may be adjusted relative to the master cam follower roller, and means including a manually operable toggle lever mechanism to move said follower arm and said lapping arm to and from'an operative position.

5. In a cam lapping machine as claimed in claim 1, the combination with the parts and features therein specified, of a lapping element comprising a continuous strip of flexible abrasive, a reel to support said abrasive, said flexible abrasive wrapping around the end of said lapping arm, a pair of opposed feed rollers engaging opposite sides of said flexible abrasive element, and means including an electric motor continuously to rotate at least one of said feed rollers so as to impart a slow continuous feeding movement to said flexible abrasive element during 'a lapping operation.

6. In a cam lapping machine as claimed in claim 1, the combination with the parts and features therein specified, of a lapping arm having a nose piece comprising an endless flexible tape, a pair of rollers on said lapping arm to support said tape, a flexible abrasive element surrounding said nose piece, and means to adjust one of said rollers relative to the other roller to tension said tape, said tape serving as a support for the flexible abrasive element.

7. In a cam lapping machine as claimed in claim 1, the combination with the parts and features therein specified, of a lapping arm having .a nose piece comprising a pair of spaced rollers, one of said rollers being mounted adjacent to the end of said lapping arm, an endless flexible tape surrounding said rollers, one of said rollers being adjustable relative to the other to tension the tape as desired, and the diameter of the roller on the end of said arm plus the thickness of the tape and abrasive element being equal to the diameter of said follower roller.

HERBERT S. INDGE. 

